Addition Of Ternary Elements Research Articles

First-principles calculations of the mechanical properties of Mg2Si intermetallic via ternary elements doping

Abstract Site preference, structural stability and mechanical properties of Mg2Si doped by ternary elements were studied by first-principles calculation. Formation enthalpies show that light element impurity Al and rare earth elements Sc and Y tend to occupy the Mg site, while transition element Cu has a preference for the Si site. Shear modulus to bulk modulus ratio (G/B), Poisson’s ratio ν and Cauchy pressure show that the ductility of Mg2Si is improved for ternary element addition. The introduced parameter of ductility factor D indicates that the enhanced dislocation emission but suppressed micro-crack propagation is the key to enhancing ductility. Electronic structure indicates the brittleness is due to the strong covalent interaction between Mg-2p and Si-3p (Mg-3s and Si-3p/3s). While, with the incorporation of alloying elements, abundant electrons are injected into the matrix Mg2Si. Thereby, the covalent interaction is effectively suppressed and the ductility is improved.

Martensitic transformation temperature modification of Fe-SMA for efficient medical implants

Nickel-Titanium alloys or Nitinol shape memory alloys have applications in various fields like biomedical, agriculture, pharmaceutical, civil, and mechanical engineering. Ferrous-based shape memory alloys (Fe-SMAs) do not possess excellent properties like that of Nitinol. In recent times, Fe-SMAs have been under consideration in the research field to enhance their shape memory properties because of their cost-effectiveness, corrosion resistance, biocompatibility, and high mechanical strength. Fe-SMAs are limited in their applications in the human body due to high austenite start temperature () even though they are biocompatible and being considered for temporary biodegradable implant applications. Several factors affect the phase transformation temperature of Fe-SMA, like alloy composition and heat treatment conditions. Some of the techniques that are useful to reduce the are quenching, solid solution treatment, ternary element addition, alloying, and thermal-mechanical treatment. In this study, the quenching with brine solution is used to reduce of Fe-15Mn-10 Cr-8Ni-4Si (wt. %). The phase transformation is observed using Differential Scanning Calorimetry (DSC). The best result from experimentation of all the samples collected as reduced from 93oC to 39.02oC which is very close to the temperature of the human body. The results of this study exhibit significant potential for advancement in the application of Fe-SMAs in the biomedical field for permanent implants in cardiovascular and orthopaedic applications.

Suppression of anti-phase boundary defects in Mn-Al-Ti permanent magnets

Permanent magnets (PMs) based on manganese show significant potential for applications in electric motors and devices as an alternative to Rare-earth PMs (REPMs). The metastable ferromagnetic τ phase of the Mn-Al system has magnetic performance between the REPM Nd-Fe-B magnets and the lower performance ferrite magnets. However, the maximum performance in Mn-Al PMs has not reached its theoretical limit, in part due to challenges in controlling crystalline defects such as anti-phase boundaries (APBs). APBs act as nucleation sites for domain reversal in Mn-Al and negatively affect magnetization by interrupting the L10 ordering, placing Mn atoms into AFM-coupled Mn-Mn configurations. In this study, Ab-initio modeling was used to screen ternary elements based on their affinity to segregate to the APB and on their preference for FM configuration. The ternary element addition of 1 at.% Ti lowered the density of APBs as observed in a transmission electron microscope. The 1 at.% Ti addition was observed to improve (BH)max over the base alloy, by preserving Hci and improving Mr. It also significantly increased the fraction of twin boundaries in the τ phase. AFM behavior that was observed in the base alloy during TC heating experiments (Néel behavior) and high-field VSM measurements (spin-flop behavior) was effectively suppressed with the addition of Ti. Additionally, the Ti addition thermally stabilized Hci at 550 °C, improving τ phase processability. Other candidate elements, Cr, V, and Zr, were modeled to have similar potential for minimizing APBs when added to Mn-Al.

Effect of Ternary Element Addition on Properties of TiNi-Based Shape Memory Alloys for Engineering and Medical Applications

Shape memory alloys (SMAs) are a type of smart material and have excellent engineering and medical applications. TiNi binary alloys possess remarkable shape recovery, mechanical properties, corrosion resistance, and excellent biocompatibility. By ternary elements addition just like Au, Pt, Pd, Hf, and Zr, increases transformation temperatures, leading to high-temperature shape memory alloys (more than 100°C) but other elements (Fe, Cu, Co, and Mo) form low-temperature shape memory alloys, (lower than 100°C). In the present work, it is reported that the effect of ternary element addition on microstructural properties, shape memory properties, mechanical properties, corrosion resistance, and biocompatibility of ternary shape memory alloys. Ag, Au, and Cu-based TiNi ternary alloys have excellent biocompatibility. The addition of ternary elements such as Ag and Nb increases corrosion resistance, Fe rises the hysteresis loop, Hf enhances thermal stability, and Mo raises workability.

Stabilization of Al3Zr allotropes in dilute aluminum alloys via the addition of ternary elements

The formation of Al3Zr particles within dilute aluminum alloys can contribute effectively to controlling microstructure evolution and enhancing material properties. However, the possible transformation of Al3Zr from its initial metastable crystal structure L12 into its stable, tetragonal structure D023 is associated with faster coherency loss and the coarsening of Al3Zr particles. In this regard, our study aims at identifying ternary elements that can disrupt this mechanism. For this purpose, nine ternary Al-Zr-X alloys (Er, Sc, Hf, Y, Nb, Mn, Cu, Zn and Si) plus a base alloy (Al-Zr) were produced. Isochronal aging was performed at 475 °C and 550 °C, and an investigation of the particle landscape was carried out by STEM and HR-TEM. In parallel, we conducted ab initio calculations to investigate fundamental properties of ternary AlZrX-particles such as substitution likeliness, heat of formation and transformation mechanisms. The elements investigated show various behaviors. Fewer than half of the elements (Er, Sc, Hf and Si) are found to be incorporated into Zr-rich particles to any large extent; Er and Sc exhibit the well-known core-shell structure. Y and Zn do not interfere at all with the precipitation process. Nb, Mn and Cu form particles on their own, with Zr particles often attached to them. Concerning crystal structures, all element additions except for Y and Si widen the stability regime of L12.

Comparison of binary, ternary and quaternary shape memory alloys and techniques to enhance their mechanical properties: A focused review

Shape memory alloys (SMAs) are smart materials having an ability to remember the original shape when deformed at the temperatures below martensite finish (Mf), which can be recovered up to certain extent by heating these alloys to temperatures above austenite finish (Af). SMAs find wide applicability in engineering sectors including automotive, aerospace, and biomedical. Prior to fabrication of any sensors and actuators using SMA, it is recommended to have an extensive simulation study that requires material properties as a prime input to the software. Scattered literature on SMA’s material properties make this challenging for new researchers. This paper presents a review of binary, ternary and quaternary alloys exhibit shape memory effect and their comparison in terms of transformation temperatures and mechanical properties. It also comments on effects in their properties due to addition of ternary and quaternary elements. Impact of thermomechanical treatments to enhance the mechanical properties and shape recovery characteristics of SMAs is reviewed. The study concludes with signifying the use of processing techniques in enhancing mechanical properties of SMAs for their utilization in possible sensing applications.

A Comparative Analysis of Ternary Element Addition on Corrosion Behavior of Aluminide Coatings in Harsh Environmental Conditions

Increasing hot corrosion durability of aluminide coatings is important to extend the lifetime of turbine blades. The addition of hafnium, yttrium, zirconium, chromium, platinum, and cobalt improves the performance of aluminide coating by increasing oxide adherence and selective oxide formation rate. In this research, the effect of adding ternary elements (Y, Cr, Y/Cr, Zr, and Hf) on type-1 hot corrosion behavior of aluminide coatings was investigated by an accelerated isothermal corrosion test at 900°C for up to 400 h. To simulate harsh environmental conditions, Na2SO4- and V2O5-containing solutions were applied to the substrate surface. Subsequently, for 1 h, 50 h, 100 h, 200 h, and 400 h exposure times, the oxide layer thicknesses, spallation time, coating layer depletion time, and elemental analysis of each set were analyzed and their performances compared.

Stabilization of Al <sub>3</sub>Zr Allotropes in Dilute Aluminum Alloys Via the Addition of Ternary Elements

The formation of Al 3 Zr particles within dilute aluminum alloys can contribute effectively to controlling microstructure evolution and enhancing material properties. However, the possible transformation of Al 3 Zr from its initial metastable crystal structure L1 2 into its stable, tetragonal structure D0 23 is associated with faster coherency loss and the coarsening of Al 3 Zr particles. In this regard, our study aims at identifying ternary elements that can disrupt this mechanism. For this purpose, nine ternary Al-Zr-X alloys (Er, Sc, Hf, Y, Nb, Mn, Cu, Zn and Si) plus a base alloy (Al-Zr) were produced. Isochronal aging was performed at 475 °C and 550 °C, and an investigation of the particle landscape was carried out by STEM and HR-TEM. In parallel, we conducted ab initio calculations to investigate fundamental properties of ternary AlZrX-particles such as substitution likeliness, heat of formation and transformation mechanisms. The elements investigated show various behaviors. Fewer than half of the elements (Er, Sc, Hf and Si) are found to be incorporated into Zr-rich particles to any large extent; Er and Sc exhibit the well-known core-shell structure. Y and Zn do not interfere at all with the precipitation process. Nb, Mn and Cu form particles on their own, with Zr particles often attached to them. Concerning crystal structures, all element additions except for Y and Si widen the stability regime of L1 2.

Strain induced localized corrosion of NiTi, NiTiCo and NiTiCr alloys in 0.9% NaCl

Shape memory and super elastic alloys are commonly used in biomedical and engineering areas, due to their higher elastic deformation characteristics and low elastic module when in martensitic state. For biomaterial applications, the alloy must exhibit adequate corrosion resistance and biocompatibility, especially in chloride environments. The addition of ternary elements in NiTi alloys aim to improve the mechanical properties. Addition of Co increases the elastic limit and reduce the transformation temperature while Cr additions increase the yield strength. However, it was demonstrated that this modification can affect the corrosion resistance of the raw materials. This study aims to assess the corrosion and strain induced corrosion resistance of NiTi alloys modified by Co and Cr additions in the presence of 0.9% NaCl solution. Ternary alloys were compared to NiTi binary alloys, when unstrained and strained within the elastic regime where martensitic transformation is induced. Electrochemical impedance spectroscopy (EIS) and anodic polarization tests were performed on both conditions. Straining electrode corrosion tests were performed under constant electrochemical potential being the electrochemical response registered. Tests using wire samples as straining working electrodes permitted the assessment of the correlation between deformation and the anodic current of the alloys immersed in 0.9% NaCl solution. It was concluded that, despite the mechanical benefits provided by the addition of ternary elements, these additions increased the susceptibility to localized corrosion and the pitting corrosion susceptibility enhanced by stress and corresponding strain.

Characteristics of eutectic and near-eutectic Zn–Al alloys as high-temperature lead-free solders

Lead-based alloys are conventionally used for soldering interconnections that are expected to perform at high temperatures. Because of the concerns of lead toxicity, the development of lead-free solders became important. Till now, none of the proposed alloys have the characteristics that can completely substitute the Pb-bearing solders for high-temperature soldering application. Recently, researchers studied many ternary and quaternary systems near Zn–Al binary eutectic composition and reported prospects in soldering applications. However, the bulk solder properties of the Zn–Al binary system near the eutectic composition is rare in the literature. In the present study, the microstructure and thermal, mechanical and electrical characteristics of eutectic and near-eutectic Zn–Al alloys are investigated as replacement of traditional lead-bearing high-temperature solders. Mechanical and electrical properties of Zn was enhanced by alloying with Al, without altering much of the thermal expansion co-efficient. Finally, the material properties of the prepared Zn–Al alloys and other Zn-based alloys are compared with the conventional Pb–Sn solders. Research shows, 7 wt% Al–Zn alloy has multiple times higher magnitude of ultimate tensile strength, Vicker’s microhardness and electrical conductivity than the traditional Pb–Sn high-temperature solders. The melting temperature of the alloys was a bit higher than the Pb–Sn solders. A suitable ternary element addition to the system can potentially replace the conventional Pb-based high-temperature solders.

Solid-State Processing Route, Mechanical Behaviour, and Oxidation Resistance of TiAl Alloys

A primary challenge associated with TiAl alloys is their low ductility at room temperature. One approach to overcome this flaw is attaining ultrafine grains in the alloy’s final microstructure. The powder metallurgy (PM) processing route favours the synthesising of ultrafine grains in TiAl alloys. This paper features the mechanical alloying (MA) process and rapid consolidation through the spark plasma sintering (SPS) technique, which comprises the PM process. Furthermore, a second approach discussed covers microalloying TiAl alloys. An evaluation of the influence of high oxygen content is also presented, including the formation ofα-Al2O3. A section of the review delves into the dynamic recrystallisation mechanisms involved in elevated temperature deformation of TiAl alloys. The final section highlights the efficacy of ternary element additions to TiAl alloys against oxidation.

Experimental and theoretical analyses of transformation temperatures of Cu-based shape memory alloys

Binary-shape memory alloys that are based on copper, mainly copper–aluminium, copper–zinc and copper–tin alloys, either with or without ternary elemental additions, are of special interest to the industry and academia because of their good shape recovery, ease of processing, larger recovery strain and lower cost. However, unlike Ni–Ti shape memory alloys, their uses are moderately limited due to shortcomings, such as stabilization of martensite due to ageing, brittleness and low mechanical strength. Therefore, efforts have been made over the years to overcome these limitations using appropriate ternary and quaternary elemental additions. This work takes into account the data obtained from the experimental work carried out by the authors of this paper as well as the data obtained from the experimental and theoretical works carried out by earlier researchers in this area that have been published in the literature over the years. It is observed in quaternary shape memory alloys based on copper that with an increase in the atomic radius of the quaternary element, the hysteresis width is found to increase. With the addition of ternary elements to binary Cu-based alloys (Cu–Al and Cu–Zn), and quaternary elements to ternary Cu-based alloys (Cu–Al–Fe, Cu–Al–Ni, Cu–Al–Mn, Cu–Zn–Al, Cu–Zn–Ni and Cu–Zn–Si), the $$M_{\mathrm{s}}$$ temperature either increases or decreases. This influence is directly correlated with the $$e_{\mathrm{v}}/a$$ ratio and $$c_{\mathrm{v}}$$ values. It is also observed that as the concentration of electrons decreases, the $$M_{\mathrm{s}}$$ temperature decreases too. In addition, in this paper, we have tried to obtain relationships between the $$M_{\mathrm{s}}$$ temperature and the mass or atomic% of different elements through multiple regressions to generalize the interpretations.

The influence of alloying on the phase formation sequence of ultra-thin nickel silicide films and on the inheritance of texture

The controlled formation of silicide materials is an ongoing challenge to facilitate the electrical contact of Si-based transistors. Due to the ongoing miniaturisation of the transistor, the silicide is trending to ever-thinner thickness's. The corresponding increase in surface-to-volume ratio emphasises the importance of low-energetic interfaces. Intriguingly, the thickness reduction of nickel silicides results in an abrupt change in phase sequence. This paper investigates the sequence of the silicides phases and their preferential orientation with respect to the Si(001) substrate, for both “thin” (i.e., 9 nm) and “ultra-thin” (i.e., 3 nm) Ni films. Furthermore, as the addition of ternary elements is often considered in order to tailor the silicides' properties, additives of Al, Co, and Pt are also included in this study. Our results show that the first silicide formed is epitaxial θ-Ni2Si, regardless of initial thickness or alloyed composition. The transformations towards subsequent silicides are changed through the additive elements, which can be understood through solubility arguments and classical nucleation theory. The crystalline alignment of the formed silicides with the substrate significantly differs through alloying. The observed textures of sequential silicides could be linked through texture inheritance. Our study illustrates the nucleation of a new phase drive to reduce the interfacial energy at the silicide-substrate interface as well as at the interface with the silicide which is being consumed for these sub-10 nm thin films.

Effects of ternary element additions on the generalized-stacking fault energy of Ti5Si3 in prismatic [formula omitted] slip system: A first-principles study

A design map in regard to the generalized-stacking fault (GSF) energy is plotted for Ti5Si3 (Ti60Si36) alloying with 12 ternary elements in {11¯00}[0001] slip system. Hereinto, alloying elements occupy preferable Ti sites near slip planes. The elements with a larger radius difference from Ti tend to reduce the GSF energies more dramatically. Moreover, the elements smaller than Ti are more prone to decreasing GSF energies than those larger than Ti. Accordingly, the addition of ternary elements, like Ni, Cu and Co, will lead to an obvious decrease in GSF energies by 18.0%, 16.7% and 13.4% respectively, and therefore may facilitate the initiation of prismatic stacking faults and furthermore enhance ductility. Note that the decline of GSF energies is attributed to the weakening covalent bonds between slip planes with the introduction of ternary elements. Our calculations provide a guide to experiments on the design of Ti5Si3 compounds with tailored properties.

Phase stability and elastic properties of β Ti–Nb–X (X = Zr, Sn) alloys: an ab initio density functional study

Alloying effects of Zr and Sn on β phase stability and elastic properties in Ti–Nb alloys are investigated within the framework of first-principles density functional theory. Our results suggest that the stability of β phase can be significantly enhanced by the addition of Zr and Sn in Ti–Nb alloys. The computed results indicate that Zr and Sn behave as strong β stabilizers in the Ti–Nb system. The elastic properties are found to be altered considerably by the addition of ternary alloying elements (Zr and Sn). The computed elastic moduli of Ti18.75 at%Nb6.25 at%Zr and Ti25 at%NbxZr compositions are found to be lower than that for Ti18.75 at%Nb6.25 at%Sn and Ti25 at%NbxSn system. The lowest value of ∼54 GPa is obtained for Ti25 at%Nb6.25 at%Zr composition. Furthermore, the directional Young’s modulus is found to be in the order of E100 < E110 < E111 for all the compositions of Ti–Nb–Zr and Ti–Nb–Sn system.

Sintering behavior and effect of ternary additions on the microstructure and mechanical properties of Ni–Fe-based alloy

ABSTRACTThe sintering behavior and effect of ternary additions on the microstructure and mechanical properties of Ni–Fe-based alloy were investigated, with the ternary additions Al, Co, Cr, Mo, Ta, and Ti. The effect of the different ternary additions was more obvious when comparing Ni40Fe10X (X = Al, Ti) and the rest of the alloys, with the former having better density and hardness than the latter. Sintered densities close to theoretical (≥98%), excluding Ni40Fe10Mo, were achieved. Interestingly, the visible porosity regions in all the samples were very small in agreement of the high sintered densities observed. The shrinkage rate was similar for all the alloys, and three peaks were observed, the first two peaks merged, and overall all the peaks were indicative of the phenomena responsible for good densification. The hardness measurement revealed that samples with poor homogeneity and those with clusters of ternary element addition in the microstructure had no hardness improvement compared to the base binary alloy. For alloys with Al, Cr, and Ti, fracture surface SEM morphology revealed the intergranular fracture of the grains and the ductile tearing of the binding phase, typical dimple structure of a ductile material; therefore, the mechanical properties of these samples are improved, while the rest of the alloys were characterized with peeling of very fine spherical particles and varying grain size and consequently compromising its mechanical properties.

Thermal Analysis of Ni-Ti-X Alloys Prepared by Self-propagating High-temperature Synthesis

In this work, the influence of alloying elements on the transformation temperatures and temperatures of formation of NiTi intermetallic phases were investigated. NiTi alloys are characterized by shape memory effect, pseudoplasticity and superelasticity. These properties strongly depend on the alloy composition in binary Ni-Ti and ternary Ni-Ti-X. Because these alloys are used in various branches of industry, such as aerospace, engineering or medicine, the addition of ternary element can influence their application significantly. Especially, the presence of Ti2Ni and Ni3Ti in the NiTi matrix may cause a degradation of the shape memory behaviour and mechanical properties. For this reason, we observed the formation of intermetallics by differential thermal analysis (DTA). Differential scanning calorimetry (DSC) experiments were performed to monitor the evolution of the transformation characteristics. We report new results, which show the strong dependence of the transformation temperatures between austenite and martensite on the alloy composition, and how the alloying elements (Mg, C, Zr) influence the formation of Ni-Ti phases.

The influence of Cu, Mg and Ni on the solidification and microstructure of Al-Si alloys

The influence of alloying elements (Cu, Mg, and Ni) on eutectic nucleation, eutectic grain morphology and the final microstructure of an Al-10Si commercial purity alloy in unmodified and Sr-modified conditions was investigated. It was found that the nucleation and eutectic grain growth morphologies of both the unmodified and Sr-modified Al-Si eutectic were significantly influenced by the addition of ternary alloying elements to a degree dependent on when the intermetallic phase formed during the solidification of the alloy with respect to the Al-Si eutectic. In cases where an intermetallic phase nucleated prior to the onset of the Al-Si eutectic reaction, the eutectic nucleation frequency was affected by changes to the available nuclei population. In cases where the intermetallic nucleated after the Al-Si eutectic, segregation of the ternary solutes in front of the Al-Si eutectic interface changed the nucleation and macroscopic growth dynamics. The changes in nucleation and growth dynamics of the Al-Si eutectic due to the presence of solute altered the morphology of the eutectic silicon considerably. This study has revealed a number of insights into the mechanisms of nucleation and growth of the Al-Si eutectic.

The influence of ternary alloying elements on the Al–Si eutectic microstructure and the Si morphology

The influence of the ternary alloying elements Cu, Mg and Fe on the Al–Si eutectic microstructure is investigated using a commercial purity Al–10wt%Si alloy in unmodified and Sr-modified conditions. A change in the Al–Si eutectic microstructure was associated with a change in the nucleation density of the eutectic grains caused by the addition of ternary alloying elements. When the ternary alloying element addition resulted in an increase in the eutectic nucleation frequency, a fibrous to flake-like transition was observed within the eutectic grain. When the ternary alloying element addition decreased the eutectic nucleation frequency significantly, a change in the eutectic morphology from flake-like to a mixture of flake-like and fibrous morphologies was observed. The mechanism of Al–Si eutectic modification is discussed. The growth velocity of the eutectic grain – liquid interface and the constitutional driving force available for growth are proposed as important parameters that influence the degree of eutectic modification in Al–Si alloys.

TiPd Shape Memory Alloy Studied by PAC Method

Perturbed angular correlation (PAC) method was applied to study the martensitic phase transition of the TiPd shape memory alloy doped with In, Hf, and Zr. The hyper ne interaction parameters and their concentration and temperature dependences for In/Cd and Hf/Ta probe atoms were determined. The in uence of ternary element additions on the electric eld gradients at Pd site was evidenced. A decrease of the martensite start temperature (MS) and an increase of the width of the hysteresis loop (TH) with an increasing concentration of the impurities in TiPd alloy was observed. These relationships are much stronger for In and Zr, than for Hf admixture.